My experience working on a Land Rover is that they all leak like sieves, from the '03-'08 models I got. I thought it was just that we were getting them used, but a guy tech who worked at Land Rover for a stint told me they have a lot of problems with those vehicles.
As for the Aluminum construction, its selective. Its still a steel frame, some panels and parts are aluminum; this was shuffled around depending on year and model. They don't even make them body on frame anymore do they?
Land Rover borrows heavily from Jaguar and BMW for powerplants and technology; BMW is just... I swear i'm gonna get PTSD with all problems those cars have. Jaguar has never been much better, leaky and rather shaky on reliability.
I'm not saying Land Rovers are the worst things on the planet (I personally want an old school or newer Defender myself,) but they are a far cry from "reliable." I'm glad you have had good luck with your previous vehicles, but my experience is when they start going bad you need to spend lots of money on parts, labor, and if you're lucky you don't have to have it outsourced to other shops for programming and factory tools.
Europeans have good ideas, but they load their cars up with so much electronic crap and over engineer things to a ridiculous degree that its bound to cause issues! One of the things I love about the 4th Gen is that its on the border of that technology/mechanical barrier. Its got techno gizmos and electronically controlled bits that do occasionally fail or go wonky, but thinks like my mechanical seat adjustments, mechanical linkage to open my door locks and actually open the door, parking brake; those all make me feel like the vehicle isn't going to fritz out and lock me in the car with no way out other than the window. (cough*BMW*cough)
Toyota, much like other manufacturers is follow the German/European formula of building vehicles which means we're going to see A LOT of reliability issues in modules, electronically controlled systems, engine controls, ect and if the extremeists get their way, we'll be using tin only solder in aeronautics and automotive industries which will greatly increase electronics failures. Read up on Tin Whiskers if you wanna learn more.
Sorry for dragging on for a bit, basically all I am saying is that the T120 Platform (4Runner, FJCR, Tacoma, ect) is a very stout and reliable platform in general compared to Land Rover's. BUT, the Land Rovers offer a lot more comforts and technology that make them just as capable if not a little more capable out of the box than the 4Runner; if their working properly. Many people on this forum do a lot of offroading in their 4Runners and honestly I'd worry about a Land Rover with their air bags, hydraulically adjusted shocks that use a secondary fluid pump off the engine, and other bits that if damaged on the trail spell disaster.
Its your choice in the end and I wish you the best of luck either way, I'm not trying to sell you a 4Runner or turn you away from a Land Rover. I'm just imparting my experience and knowledge of these vehicles. Its up to you to decide what vehicle better suits your needs and wants, a lot of people seem to forget that when buying a car or truck. (i.e. buying a V8 and then getting upset because it drains gas)
Best of luck to you!![]()